Véronique Baron-Bodo

A regulatory dendritic cell signature correlates with the clinical efficacy of allergen-specific sublingual immunotherapy.

BACKGROUND Given their pivotal role in the polarization of T-cell responses, molecular changes at the level of dendritic cells (DCs) could represent an early signature indicative of the subsequent orientation of adaptive immune responses during immunotherapy. OBJECTIVE We sought to investigate whether markers of effector and regulatory DCs are affected during allergen immunotherapy in relationship with clinical benefit. METHODS Differential gel electrophoresis and label-free mass spectrometry approaches were used to compare whole proteomes from human monocyte-derived DCs differentiated toward either regulatory or effector functions. The expression of those markers was assessed by using quantitative PCR in PBMCs from 79 patients with grass pollen allergy enrolled in a double-blind, placebo-controlled clinical study evaluating the efficacy of sublingual tablets in an allergen exposure chamber over a 4-month period. RESULTS We identified several markers associated with DC1 and/or DC17 effector DCs, including CD71, FSCN1, IRF4, NMES1, MX1, TRAF1. A substantial phenotypic heterogeneity was observed among various types of tolerogenic DCs, with ANXA1, Complement component 1 (C1Q), CATC, GILZ, F13A, FKBP5, Stabilin-1 (STAB1), and TPP1 molecules established as shared or restricted regulatory DC markers. The expression of 2 of those DCs markers, C1Q and STAB1, was increased in PBMCs from clinical responders in contrast to that seen in nonresponders or placebo-treated patients. CONCLUSION C1Q and STAB1 represent candidate biomarkers of early efficacy of allergen immunotherapy as the hallmark of a regulatory innate immune response predictive of clinical tolerance.

Changes in basophil activation during grass‐pollen sublingual immunotherapy do not correlate with clinical efficacy

To cite this article: Van Overtvelt L, Baron‐Bodo V, Horiot S, Moussu H, Ricarte C, Horak F, Zieglmayer P, Zieglmayer R, Montagut A, Galvain S, de Beaumont O, Le Gall M, Moingeon P. Changes in basophil activation during grass‐pollen sublingual immunotherapy do not correlate with clinical efficacy. Allergy 2011; 66: 1530–1537.

Allergen‐specific CD4+ T cell responses in peripheral blood do not predict the early onset of clinical efficacy during grass pollen sublingual immunotherapy

Surrogate biomarkers of efficacy are needed in support of allergen‐specific immunotherapy.

Patterns of IgE sensitization in house dust mite-allergic patients: implications for allergen immunotherapy

Understanding patterns of IgE sensitization in Dermatophagoides‐allergic patients living in various geographical areas is necessary to design a product suitable for worldwide allergen immunotherapy (AIT).

Identification of the cysteine protease Amb a 11 as a novel major allergen from short ragweed

BACKGROUND Allergy to pollen from short ragweed (Ambrosia artemisiifolia) is a serious and expanding health problem in the United States and in Europe. OBJECTIVE We sought to investigate the presence of undescribed allergens in ragweed pollen. METHODS Ragweed pollen proteins were submitted to high-resolution gel electrophoresis and tested for IgE reactivity by using sera from 92 American or European donors with ragweed allergy. Pollen transcriptome sequencing, mass spectrometry (MS), and recombinant DNA technologies were applied to characterize new IgE-binding proteins. RESULTS High-resolution IgE immunoblotting experiments revealed that 50 (54%) of 92 patients with ragweed allergy were sensitized to a 37-kDa allergen distinct from Amb a 1. The full-length cDNA sequence for this molecule was obtained by means of PCR cloning after MS sequencing of the protein combined with ragweed pollen RNA sequencing. The purified allergen, termed Amb a 11, was fully characterized by MS and confirmed to react with IgEs from 66% of patients. This molecule is a 262-amino-acid thiol protease of the papain family expressed as a combination of isoforms and glycoforms after proteolytic removal of N- and C-terminal propeptides from a proform. Three-dimensional modeling revealed a high structural homology with known cysteine proteases, including the mite Der p 1 allergen. The protease activity of Amb a 11, as well as its capacity to activate basophils from patients with ragweed allergy, were confirmed. The production of a nonglycosylated recombinant form of Amb a 11 in Escherichia coli established that glycosylation is not required for IgE binding. CONCLUSION We identified the cysteine protease Amb a 11 as a new major allergen from ragweed pollen. Given the similar physicochemical properties shared by the 2 major allergens, we hypothesize that part of the allergenic activity previously ascribed to Amb a 1 is rather borne by Amb a 11.

Absence of IgE neosensitization in house dust mite allergic patients following sublingual immunotherapy

The impact of sublingual immunotherapy (SLIT) on IgE neosensitization remains to be evaluated in large cohorts of patients.

Heterogeneity of antibody responses among clinical responders during grass pollen sublingual immunotherapy

During allergen‐specific sublingual immunotherapy (SLIT), the relevance of changes in specific IgE and IgG antibody titres to treatment efficacy remains to be evaluated at an individual patient level.

Comparison between major histocompatibility complex class II tetramer staining and surface expression of activation markers for the detection of allergen‐specific CD4+ T cells

Cite this as: M. Bonvalet, E. Wambre, H. Moussu, S. Horiot, W. W. Kwok, A. Louise, D. Ebo, C. Hoarau, L. Van Overtvelt, V. Baron‐Bodo and P. Moingeon, Clinical & Experimental Allergy, 2011 (41) 821–829.

Expression and characterization of natural-like recombinant Der p 2 for sublingual immunotherapy.

Background: Recombinant allergens with a native conformation represent an alternative to natural extracts for immunotherapy and diagnostic purposes. Methods: We produced the Der p 2 mite allergen in Pichia pastoris and Escherichia coli. After purification by cation exchange chromatography, recombinant molecules were compared to their natural counterpart based upon structural (disulfide bonds, secondary structure, thermal stability) and immunological properties (antibody reactivity, basophil and T cell activation, tolerance induction in a murine sublingual immunotherapy model). Results: The Der p 2.0101 isoform was confirmed to be prevalent in Dermatophagoides pteronyssinus extracts. It was then produced as a secreted molecule in P. pastoris or refolded from E. coli inclusion bodies. The yeast-expressed rDer p 2 molecule exhibits a natural-like disulfide bridge distribution and secondary structure, whereas the E. coli-derived rDer p 2 presents some heterogeneity in cysteine bonds and a lower stability following thermal stress. The two recombinant as well as natural Der p 2 molecules exhibit comparable IgE recognition and activate basophil and CD4+ T cells. Sublingual immunotherapy of nDer p 2- sensitized mice using either one of the rDer p 2 molecules efficiently decreases airway hyperresponsiveness as well as Th2 responses. Conclusions: Natural and recombinant Der p 2 molecules produced in P. pastoris and E. coli exhibit comparable immunological properties despite distinct structural features. Natural-like cysteine pairing is a critical parameter to identify stable, well-folded and homogenous proteins appropriate for immunotherapy and diagnostic purposes.

Evaluation of therapeutic sublingual vaccines in a murine model of chronic house dust mite allergic airway inflammation

Second generation therapeutic vaccines based upon recombinant allergens or natural extracts, potentially formulated in vector systems or adjuvants, are being developed. To this aim, preclinical studies in relevant animal models are needed to select proper allergens, formulations and administration schemes.